No. 9.] J. W. DAWSON — PALEOZOIC LAND SNAILS. 457 



furnished with a single central curved tooth, projecting nearly 

 half way across the aperture. Junction of columella and outer 

 lip somewhat angular and dentiform. In old individuals the 

 columella tooth is often continuous through an entire turn or 

 farther. It is not seen on shells having less than three turns. 

 The last turn forms nearly half the length of the shell. Whorls 

 rounded. Suture impressed. Surface glossy. Color black or 

 gray. Length three and six-tenths millimeters. Width two 

 millimeters. Some individuals are smooth or destitute of the 

 fine microscopic ridges, but whether this is a natural peculiarity 

 or a result of injury to the outer surface, is not certain. 



As compared with Pupa vetusfa this shell is less than half 

 the size, of a less cylindrical form, its whorls more rounded, and 

 its body whorl much larger in proportion. Its sculpture is much 

 finer. The conspicuous tooth in the aperture is of course a 

 strong mark of distinction. The shell is thin, and from its 

 black color and failure to show structure under the microscope, 

 I infer that it must have been of a horny or corneous texture, 

 with little calcareous matter. The matrix is light-cuiored and 

 concretionary, and somewhat hard and calcareous. 



As compared with modern American species, F. Vermilion ensis 

 is very near to several of the smaller forms with teeth in the 

 aperture. In its form and aperture it approaches closely to P. 

 (^Leucochild) cortlcaria of Say, or to the immature shell of P. 

 rupicola. It has also some resemblance to the western species 

 P. liordeacea Gabb, from Arizona. 



This shell was discovered by the late Mr. F. H. Bradley in 

 1869, in concretionary limestone accompanying the underclay of 

 Coal No. 6, Wabash Valley Section, at Felly's Fort, Vermilion 

 River, Illinois. In the first notice, which appeared in the 

 Report of the Geological Survey of Illinois, it was referred to 

 Pupa vetusta, but was subsequently described by Mr. Bradley 

 in the American Journal of Science, under the name above cited. 



I am indebted for specimens of this shell to Mr. John Collett, 

 of the Geological Survey of Indiana, and also to Mr. W. Gurley, 

 of Danville, Illinois. 



4. Zonites (Conulus) lyrisciis Carpenter. (Figs. 10 and 11, 



and 14c?.) 



[Quarterly Journal of Geological Society of London, Nov. 1867. 

 Acadian Geology, 2nd edition, 1868, p. 385.] 



